Academia Sinica touts breakthrough in war on bacteria

By Meggie Lu / STAFF REPORTER

In the war between the human race and malignant bacteria, researchers at Academia Sinica's Genomics Research Center yesterday struck a blow when they announced a breakthrough that could lead to a range of replacements for an antibiotic to which such bacteria have developed resistance.

The center's research has been published in the Journal of the American Chemical Society.

"Our characterization of four key enzymes involved in the biosynthesis of A40926, an antibiotic similar to vancomycin, allows us to genetically engineer and develop drug candidates," research center fellow Li Tsung-lin (李宗璘) told the Taipei Times.

Li said that when bacteria are exposed to antibiotics, they gradually develop resistance. Their hosts then take stronger antibiotics, only to encourage further resistance, leading to a sort of stalemate.

"In earlier times simple antibiotics were used to cure most infections, but bacteria nowadays have gotten clever," Li said, citing the discovery of Vancomycin-Resistant Enterococcus (VRE) in 1985. "VRE was a strain of intestinal bacteria found to be resistant to vancomycin, a glycopeptide antibiotic traditionally seen as our last resort or `trump card' against bacteria."

"Our breakthrough allows us to produce analogues of A40926, an antibiotic structurally similar to vancomycin, which means we would have many drug candidates potentially effective in fighting bacteria resistant to A40926," said Tsai Ming-Daw (蔡明道), acting director of the Institute of Biological Chemistry.

The increased diversity of A40926 is a key achievement, Tsai said, since "most bacteria eventually develop drug resistance, but genetic mapping allows us to produce a good number of analogues unrecognizable to them, meaning we'll always have something that works."

VISA was first identified in Japan in 1996, Li said, adding that VISA is a variation of the common Staphylococcus aureus that causes much more difficult-to-treat infections.

While Staphylococcus aureus is a usually benign strain of gram-positive bacteria found in membranes and open wounds, it is the cause of the second most common bacterial infections in Taiwan next to E. Coli, he said.

"When Staphylococcus aureus penetrates the skin of immune-compromised individuals, they can contract inflammation, cellulitis, or in severe cases, bacteremia and sepsis," Li said.

"We are hopeful that the drug candidates can be developed into antibiotics that are effective in treating hard-to-treat infections," he said.